Most ear disorders are the result of an inflammatory response to infections, allergic reactions, or trauma. The infection may be of bacterial, fungal or viral origin and determination of the precise etiology is not practical since the causative organism is often difficult to isolate and culture. The determination of a viral cause is even more difficult to establish. Trauma, as a cause of ear disorders is made on the basis of a medical history and radiological confirmation.
It is important to treat the inflammation as soon as possible to reduce the sequella of hearing loss, tinnitus, facial nerve palsy, mastoiditis, labyrinthitis, vertigo, and possible encephalitis. Otitis is a non-specific term that describes a symptom and indicates an inflammation of the ear. The ear is anatomically divided into the external, middle and inner ear.
The external ear consists of the auricle and the external canal, a tube like structure that ends at the tympanic membrane (eardrum). Otitis externa (swimmer's ear) is an inflammation of the external canal which occurs in hot, humid weather, after cooling off in the pool and by those who enjoy aerobic exercises. Normally, cerumen (ear wax) and the acid pH of the external auditory canal protect the ear from infection. The canal can become inflamed and infected when the epithelium lining the canal becomes injured, as can occur after attempts to remove cerumen or entrapped water from the ear canal. The epithelium becomes macerated and susceptible to infection. The epithelium of the external auditory canal is tightly attached to the underlying bone or cartilage, and even a little swelling produces a great deal of pain. The macerated epithelial cells form a red and scaly dermatitis that may encroach on the epithelium of the tympanic membrane. A cellulose tampon (Pope ear wick) is sometimes inserted into the auditory canal and moistened with antibiotics to control the infection and drying-medications or steroids to relieve the swelling. Fungal infections usually resolve when the acidic pH is restored. In diabetic or immunocompromised persons, otitis externa may progress to cellulitis of the scalp and osteomyelitis of the skull. Untreated or chronic otitis externa can cause an inflammation of the tympanic membrane and initiate an inflammation of the middle and inner ear.
The middle ear or tympanic cavity, is an air-filled cavity in the temporal bone that contains three small bones (malleus, incus and stapes) that transfer sound from the tympanic membrane to the oval window of the inner ear. The tympanic cavity resembles a red blood cell in appearance, since it is narrow and rounded, compressed at the center and enlarged peripherally. It is likened to a sump pit, 2 mm across the center, 15 mm in vertical diameter, 4 mm at the floor and 6 mm at the roof. The floor of the cavity overlies the jugular vein, the anterior wall is the internal carotid artery, the posterior wall contains the facial nerve, the tympanic membrane occupies the lateral wall and inner ear the middle wall. The eustachian tube connects the middle ear with the back of the nasopharynx. The tube's function is to allow air to enter the middle ear and maintain equal atmospheric pressure on both sides of the tympanic membrane. An inflammation of the lining of the eustachian tube, due to infection or allergies, causes the tube to close and either creates a vacuum or the accumulation of fluid in the middle ear resulting in otitis media.
Otitis media is a painful inflammation of the middle ear and ranks second only to the common cold as the most frequent illness among children in the United States. Acute otitis media is usually accompanied by fever, swelling, inflammation of the eardrum and considerable pain. Otitis media develops when bacteria or viruses, usually associated with colds or sore throats, make their way up the eustachian tube, from the upper part of the throat behind the nose to the middle ear. When fluid accumulates in the middle ear the condition is known as otitis media with effusion or "glue ear." This condition can lead to hearing loss and affect a child's learning and language skills.
Nearly 70 percent of U.S. children will develop otitis media by age 2. Otitis media is a frequent problem in children because the eustachian tube is shorter, wider, and more horizontal than in adults. Many children will outgrow their susceptibility to the infection by age 5. Over half of those who experience acute otitis media will have repeated episodes and the condition may become chronic. Otitis media is the most common cause of hearing loss in the U.S. and represents a significant disability interfering with childhood learning processes. Estrada B, Infect Med 1997; 14(3):239-44. Otitis media accounts for over 35 percent of all visits to pediatricians each year and represents more than $3.5 billion in U.S. health care costs annually.
Otitis media, with or without effusion is the most common reason for prescribing antibiotics to children. The FDA found that about 14 percent of all courses of antibiotics prescribed in the United States were for otitis media. Seventy percent of ear infections have a bacterial etiology and 30 percent are viral in origin. Three types of bacteria, Streptococcus pneumoniae, Hemophilus influenza and Moraxella catarrhalis cause 50 to 90 percent of middle ear infections. Many of these bacteria are now resistant to antibiotics. Some children experience life threatening reactions to the antibiotics.
When medical management is not successful, plastic tubes are surgically inserted into the tympanic membrane to drain the middle ear. This surgical procedure known as tympanostomy, is the most common surgery performed on children under age 2. In 1988, 800,000 children received 1.3 million tympanostomy tubes. Of these, 30 percent were replacements. Risks of using ear tubes include: risks associated with general anesthesia; tympanosclerosis in 51 percent of patients; persistent otorrhea in 13 percent of patients and an average 5-db hearing loss. Thirty percent of children receiving one set of tubes will receive a second set within 5 years. A study published in JAMA, Apr. 27, 1994, found that 25 percent of tympanostomies were inappropriate, and in 30 percent the benefits did not outweigh the risks of general anesthesia. In 1986, 31 million visits to physicians were due to otitis media, and total direct and indirect costs for that year have been estimated at $3.5 billion. Surgical costs for procedures for otitis media exceed $1.2 billion annually.
The inner ear is concerned with the reception of sound and balance. The movement of the ear ossicles excite the perilymph fluid in the cochlea, which stimulate the nerve endings in the hair cells of the organ of Corti. The acoustic nerve then caries impulses to the brain for purposes of interpreting sound. The labyrinth is the collective name for the sense organs of equilibrium, consisting of the three semicircular canals and the utricle and saccule which connect with the cerebellum and the brainstem. Since the organs for hearing and balance are within the same compartment of the temporal bone, they are often affected by the same disorders. Inflammation in the middle ear frequently causes inflammation in the inner ear resulting in disorders of hearing and balance.
As far as the inventor is aware the prior art has not provided any topical composition which specifically directs therapeutic agents simultaneously to the external, middle, and inner ear, to treat and prevent the effects of inflammation and infection.